Electric distribution system



June 23, 1925.

P. H. CHASE ELECTRIC DISTRIBUTION SYSTEM 4 Sheets-Sheet 1 Filed July 1, 1924 1,543,370 R H. CHASE l 924 4 Sheets-Sheet 2 June 23, 1925.

4 Sheets-Sheet :5

June 23, 1925.

P. H. CHASE ELECTRXC DISTRIBUTION SYSTEM Filed. July 1924 June 23, 1925 F. H. CHASE DISTRIBUTION ELECTRIC Filed July 1,, 1924 4 She-etvSheet km @N\ patented .lunei23, 1925.

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, Application filed 'rul 1, 1924. mm m. m,na.

To all whom it may co /teem:

Be it known that I, PHILIP H. Omen, a Q

citizen of the United States, and a resident of Bala, Montgomery County, Pennsylva- 6 nia, havev invented an Improvement in Elec' tric Distribution Systems, of which the following is a 'specification.

This invention relates to electric distribution s stems, and with regard, tomore specific eatures, to circuit and control arrangements and connections.

Among the several objects of-the invention may be noted the rovision of simple and effective means for isolating sections of an electric' power distribution system and thereby minimizing-interruptions due to a 'failure of equipment, feeders or mains; the

attainment of a high degree of reliability of service with 'a comparatively smallnumber of circuit-interrupting devices; thereduction of mileage in electric power distribution system primary feeders and mains supplying a primary or secondary system of mains; and the provision of simple, rugged and'highly selective means of protection'to an electric distribution system of minimum expense, adapted to withstand severe service conditions. Other objects will be inpart obviousand in part pointed out hereinafter. The invention accordingly comprises the features of construction, combinations of elements and arrangements of parts, which a re exemplified in the description hereinafter in connection with the accompanying drawings, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various embodiments of this invention,

Fig. 1 is a one-line schematic diagram of a preferred embodiment of the invention;

Fig. 2 is a full-line schematic diagram of a feeder section of Figure 1, for a threephase circuit. a

- Fig. 3 is a full-line schematic diagram of other preferred embodiments of the invention, substituting fuses for the secondary transformer circuit'breakers in Fig. 1 and illustrating the omission of transformers.

F i .4 is a full-line schematic diagram of anot er embodiment of the invention, illustrating more than one transformer or loa tap on a feeder section. A

.ing an electric distribution system, through 5 with two sets of trip coils 20. an

Fig. 5 is a one-line schematic diagram-of i other embodiments ofthe invention,-illuatrating more than one feedenand tie connectionsbetween feeders,

Fig. 6 isa one-line schematic diagram of a feeder section, illustrating the use of potential balance. a 1

Referring now more particularly to 1 and 2 of the accompanying drawi there is illustrated at 1 a sub-station sun igstation circuit-breakers 3, feeders .4, and feeder sections 5. The feeder sections 5 are connected in serieswlth each other and the feeders-4 bymeans of section circuit-breakers 7,,{t1hus to ther forming'a loop feeder with an ply mm the rsub-station atfhoth ends un er normal conditions.

Each feeder section 5 has a tap 6. sup 1y ing, a transformer 'or 'transformer ban 8, the secondary side of which su plies a load, loads or secondary mains 10, t rouglfih cirwit-interrupting device 9. The secondary mains 1O supplied" from each'transformer or transformer bank 8, are preferablyconnected together or may be operated separately, depending upon service requirements, cost and operating features.

The feeders, feeder sections, and mains may be in cable ormay be open wire, the circuit-interrupting devices may be oilbreak or air-break ty of circuit breakers, or other suitable-circuit-interrupting device, for aerial, subway or building installation,

and the transformers may be either aerial,

subway or indoor type. The feeder and sec-. 9 ondary voltages, the number of phases and the frequency may be any that are suitable for the service and installation requirements.

Each section circuit-breaker 7 is equi ped 21. each set actuated separately by the currents in the pilot wire control circuits 26, 27, 28, from the current transformers 15, 16;17,connected respectively thereto; Each secondary transformer circuit-breaker- 9, is equipped with one set of trip coils .22, connected to and actuated by the same pilot wire control circuits and current transformers. The cir cuitbreakers uiay be formanual or electrical closing, and-if equipped for electrical closiiga-the trip coils 20, 21 or 22,

may be repla by (not shown) .that the current in the seconds.

which inturn energize a single tri coil on each'circuit-breaker from a contro source.

The current transformers are preferably be incorporated under the same sheath with the main conductor if they are in cable.

The current transformers l5 and 16, at the twoends of the feeder-section 5, have the same ratio and should preferably be identical, and throughthe pilot'wires 26 and 27 they are connected 'in such a way that under normal conditions the potentials are the. same in direction and magnitude. The current transformers 17, on the secondary side of the transformers are of such a ratio winding of the current transformers 17 is substantially the same per ampere in the primary taps 6 to the transformers 8,' as is the current in current transformers 15 and'16 per ampere of current passing through their primaries.v The current transformers 17 are connected by pilot wires 28 to the pilot wires 27 which are connectedto the current transis ap arent that in the trans ormers-15, 16, 17'and pilotwires'26,

- feeder section under. consideration and rc-.

27 and 28, there is a condition'of similitud in the ma itude and direction of thejcur-' rents in afl parts' to the currents in corresponding parts of the main feeder section 5 and the, tap 6,

. The pilot system balances, in its componentparts, for the normal conditionin the corresponding main circuit: that is, the total current output is equal in magnitude and direction to the total current input, giving a resultant substantially zero. "The actual deviation from a condition of exact balance is usually relatively small and results from factors, such as losses in the'feede'qsection and transformers, and in transformers and current-transformer ratios.

Under normal conditions, therefore, there is substantially a condition of'current balance in the pilot wire system regardless of the magnitude and direction of (low of power between other feeder sections and the gardless of the magnitude and-directlon of flow of power through the circuit breaker 9. As a result there is a very low voltage across the terminals of the various current transformers 15, -16 and 17 and accordingly the ma nitude of the current through the. Y relative direction, or both, of the potentials in the system of current current transformers 15, 16. and 17 on the section changessubstantially f om the normal balance condition. Under fault conditions the magnitude of the unbalance may be very large.

The potential across ,each current transformer rises and causes the unbalanced components of the currents to pass through the trip coils 15, 16 and 17 connected to the pi ot wires on the faulty section, thereby actuating them, opening the two section circuitbreakers .7 and the circuit-breaker 9, and isolating the faulty feeder section and-tho transformer bank. 1 i

The' fault may involve one or more phase wires and result in unbalanceonly on the corresponding phase or phases of the pilotcircuit and still actuate the corresponding trip coils. p f

Under such fault conditions the nornal balance in the other feeder sections has not been substantially disturbed, and no feeder section breakers? except those connected to the faulty'feeder section have opened, norhas service to loads supplied'from the other sections been interrupted. Further, with the transformer banks connected to the same mains 10, the tripping of circuit breaker 9 has cleared the faulty section from the mains but the load normally carriedby the transformer bank 8 on the faulty section is picked up by the other banks, without interruption of service to those loads' supplied from the mains 10. I

It is therefore apparent that any fault or failure occurring on the feeder section 5, on the tap 6, or'in the transformer bank 8, or at any point between the current transformers 15, 16 and 17 on a given section, will result in the isolation of that section from the rest of the system.

As each section circuit-breaker is provided with a set-0f trip coils for each of the pilot wire systems pertaining to the feeder section to either side of it, each section breaker serves to isolate two feeder sections. The number of feeder section breakers is therefore minimized and the cost and com.

plication are materially reduced. As theoperation of the protective equipment on each feeder section is determined by conditions within that section, the feeder may comprise as many sections as is considered desirable.

-- The feeder 4 (Fig. 1) is illustrated as provided with pilot wires 25 from the sub-station feeder current transformers 19, to the feeder current transformers 18, and 'trip- V coils 2 0 and 21 on the feedcrls'ection circuit breakers 7 on feeders 4 and trip coils' 23 0n the sub-station feeder circuit breakers 3. These fecders are illustratcdv ith no taps to transformers or loads and therefore there is a two-way balance instead' jii'fptlie threeway balance on the pilot wire systems pertaining to the feeder sections. Selective operation of the sub-station feeder breaker 3 tection for the feeder and either with or without the pilotv wires from the substation to the first sectionbreakers'l. Such methods may be followed without loss of the advantages of thefeeder section protection described. There may' also be provided on part or all of the'feedr section breakers 7 and transformer secondary breakers 9, additional types of relay protection such as excess current and power directional, in order to provide for sectionalizing. of feeder sections or v groups of feeder sections, for'example under extraordinary emergency conditions.

Deviations from exact current balance in the pilot wire system 25, 26, 27 may be lrept within desired limits bythe use of'supplemental current transformers or autotransformers with taps, and loadingfcoils or equivalent devices (not sliown). such j means the deviations due up diiferencesin current transformers, transformer ratios, losses in the circuits and other such variables may readily be compensated for.

In Fig; 3 is illustrated a feeder section and a portion of another feeder section in one of which the seoondarytransformer fuses 30 are substituted for the transformer sec ondary circuit-breaker 9, arid in the other of which the transformers 8 are omitted. The use of fuses 30 instead of the transformer secondary circuit-breaker will often. be preferable when the interrd-pting duty or the voltage is low. lVith thisv arrangement, it is apparent that the only difference in the operation isthat the blowing of the fuses is dependent upon the current through them and inno wayafi'ects the balancein the pilot wire control circuits nor the operation of the feeder sectioncircuit-breakers 7. The

omission of the transformers 8 does not affect the operation of the circiiit breakers 7 and 9, but requires current transformers 17 of the same ratio as the current transformers 15 and 16 on the.feeder section.

Figure 4 illustrates afeeder section 5 with two taps 6 each sup lying a transformer bank 8 protected outhe secondary'side by a circuit-breaker 9 as in Figures 1 and '2.

The pilot wire control system'26, 27, 28, 29 provides a substantial balance-equivalent t0 that in the corresponding portions ofthe.

- before described.

tamed.

main circuit. It is apparent that a number of load taps may be made to a feeder section, with corresponding 'pilot wire and current transformer equipment, and still secure the same operative features as described in connection with Figures 1, 2 and 3.

Figure 5 illustrates two loop feeders similarto those shown in the preceding figures, each comprising feeders 4, feeder sections 5, taps 6, transformers 8 and secondaryfuses 30. The two feeders are illustrated supplying a secondary main system or network lO, which as in the preceding figuresis-conne'cted to translating devices (not shown). In the event of'a failure on anyfeeder section, the section circuit-breakers 7 onthat section are actuated by the unbalance in current in the trip coils 20 and 21, and the fuses 30 on the transformer on that section blow due to the short-circuit current through them from 95 the mains 10, supplied from-the other'transformers connected to the same mains, herein- Figure 5 also illustrates a tiefcircuit breaker 11, which connects between two feeder sections 5 of difi'erentfeeders by s, 12. TheII ilot wire control system 26,} 28, with t ecurrent transformers 15, 16,117. and trip coils 20, 21 and 24, actuate'tho breakers 7, 9 and 11 on whichever of, .th' two connecting sections5, 12, that a faultpccurs, similarly to the connections above By the methods and apparatus shown ,in Figures 1 to 5 inclusive, variouS,combina-. tions, distribution feeder networks,'.both'p'i'-i- 'mary and secondary, may..be built afford such connections as may be design,

with great flexibility and selectivity, I A Figure 6 illustrates another balance method applied to a typical feeder section.

In this connection, the current transformers 1'5, 16 and 17 are'connectedin series with each other and withthetripcoils 15 and 16 on-the section circuit-breakers so that under normal conditions the sum of the tentials around a control circuit is .su stantially zero under normal conditions, and therefore there is ne ligible current assing throu h the tri coii; 20 andv 21. 1?, however, t ere is a ault 13, the potential balance is'disturbed and current passes thro h the trip coils, thus actuating the circuit reakers. This method requires different type current transformers andhi her insulation on the control circuits and trip coils thanis the case with the current balance illustrated in Figs. 1 to 5.inclusive.

.In view of the above it will be seen that the several ob'eds of the invention achieved and 0 er advantageous results, at-

Asmany changes could be made ini car ing put'the above constructions withoutiliiartmgjfrom the scope of theinventiom: it

ii intandedrthat mm mined m illustrative and not'iii alimiting sense.

for operating said circuit interrupting detion to the loa associated with said loop section an tap for vices; said solating means com rising a transformer adjacenteither end the loop 'section,'-a transformer in the tap, a ilot circuit in which 'tllQSGCOIIdRIlGS of t e transformers are connected, and tripjdevices energized from the pilot circuit and adapted to o n the circuit-interrupting. devices at either endof the loop section.

2. An electric distribution system comprising' a ,sectionalized power loop adapted to be met ized from one or more-sources of power;aj oad'- atap' connecting a loop secd; circuit-interruptin device s isolating" said section from the loop and from the load; and isolating means for operof the-loop section an ating said circuit-interrupting devices ;'1 said isolating .means comprising atransformer adjalbent either-end of the loop section, a

transformer in the tap a pilot circuit in which the secondaries of the transformers are connected, and trip .devices energized from the ,pilotcircuit and adapted to -open the circuit-interrupting devices at either end in the tap.

3. An electric distribution system comprising aisectionalizedipower loop adapted to be ener 'zed from one or more sources of war; a oad; a tap connecting a loop section'to the load; means for opening thetap; circuit interri pting devices associated with said loop section or isolating said section from the loop; and isolating means for opcia ating said circuitinterrupting,devices said isolating means comprising atransformer adjacent either end of the loop section, a

transformer in the tap, a pilot circuit;- in which the secondaries of the transformers are connected, and trip devices energized from the pilot circuit and adapted to open the circuit interri pting devices at either end of the loopsection.

;4. An electric distribution s 'stem comprising a sectionalized power oop; a tap connecting a section of said loop to another. circuit; means for openingzthe tap-circuitinterrupting devices associated with said loop section for isolating saidsection from the loopand from said circuit; and isolating means for operating said circuit-interru ting device's; said isolating meaii's cpmprising a transformer adjacent either end, of the loop section,'a traiisformer in th'e tap, a pilot g I v v v 'circuit and adapted to open'the circuit-i er- 'circuit in which the secondaries of the't-ranseither end of the loop 7 5. An electric distribution system commeans comprisin formers pre connected, and trip devices energized rom the pilot circuit and adapted to open the circuit-interrupting devices at section.

prisinga plurality of sectionalized power loops; a load; taps connecting a section of each loopv to the load; circuit-interrupting devices associated .with said taps for isolating the respective tap from the load; and isolating means' for operating said lastnamed circuit-interrupting devices; each said isolating means comprising a .transformer adjacent either end of the respective loop section, a transformer in said tap, a

pilot circuit in which the secondaries of the transformers are connected, and trip devices energized from the pilot circuit and adapted to open the circuit-interrupting devices at either end of the loop section and in the tap. r v

6. An electric distribution system comprising a plurality of sectionalized powerloops each adapted to be energized from one or moresources of power; mains; 'a tap; a

mains; means for opening the tap; circuitinterrupting devices. associated with said loopsection for isolating said section from the loop; isolating means for operating =feederconnecting a loop section to the ergized from-the'pilot circuit and adapted' to openthe circuitinterri pting devices "at either end of 'the loop section and in the latter tap.

7. An electric distribution system comprising'a plurality of sectionalized power loops ea'chadaptedto: be energized from one or more sources of power; mains; a tap connecting a loop section to the mains; -..means for opening-the. tap; Circuit/#115361? ruptingdevices associated with said loop section for isblatingsaid section from, the

loop;iisolating means for operatingsaidcii? .ci it-interrupting devices;: -sa1d isolating a transformer -ad acent either endiof theoop section, a transformer andgtliip-qdevices energized from the ilot rup'ting devices at either end vofj'the loop section; a tap connecting a section of one loop toa section. of another loop; circuitbrcaking means in said tap; circuit-inter rupting devices associated with said lastnamed sections for isolating the respective sections from its loop; and isolating means for operating said last-named circuit-interruptingdevices and said last-named circuithreaking means; saidisolating means comprising a transformer adjacent either end of the respective loop section, a transformer-in said tap, a pilot circuit in which the secondaries of the transformers are connected, and trip devices energized from the pilot circuit and adapted to open the circuit-interrupting devices at either end of the 1001) section and in the tap. 1 j."-

8. An electric distribution system com"- risin a sectionalizedv owerloo a lll-a rality of taps adapted to connect a loop section to'translating devices; circuit-interrupting devices associated with said loop section for isolating said section from the loop; and isolating means for operating said circuit-internipting devices; said isolating means comprisin -a transformer adjacent either end of the oop section,a transformer in each tap, a ilot circuit in which! the secondaries of t e transformers are connected, and tri devices energized from the pilot circuit an adapted open the circuitinterrupting devices at either end of the loop section.

9. An electric distribution system comprising a sectionalized power loop adapted to he energized from one or more sources of power; a. plurality of taps adapted to conncct a loop section to translatin devices; circuitinternipting devices associated with said loop section and taps for isolati g said section from the loop and from said translating devices and isolating means for operating said circuit-interrupt ng devices: said isolating; means' comprising a trans? former adjacent either end of the loop section. a transformer in each tap, a pilot circuit in vwhich the secondaries of the transformers are connected. and trip devices energized from the pilot circuit and adapted to open the circuit-interrupting devices at either end of the loop section and in the taps from said section.

10. An electric distribution system com prising circuit-interrupting devices, a feeder section adapted to be connected through said circuit interrupting devices to a pluralit of sources of power and to a load; and a alance protective system associated with each 3 lower-supply-circuit-interrupting device and with the load terminus of the section, and adapted upon an unbalance in the protective system to isolate the feeder section from its sources of power.

ll. An electric prising circuit-interrupting devices, a feeder section adapted. to a be connected through circuit-interrupting devices to a plurality of power sources and to taps topower-utilizing devices: and a balance .protective system associated with each 'power-su pl -circuit-interrupting device and tap an a apted upon 'comprisin a current transformer adj acenteither n J of the loop section,- a; current transformer in the .tap, a pilot circuit in which'the secondaries of the transformers are. connected, and trip devices energized from the pilot oircuit and adapted to open the circuit-interrupting'devices at either end. of the loop section upon a predetermined abnormal condition;

"13. An electric distribution systemcomprising a .sectionalized power loop adapted to be energized from one or more sources of power; mains; a tap connecting a. loop section to the mains; c urrent-interrupting devices associated' with said loop section and tap for isolatingsaid section from the loop and from the mains; and current-balance-responsive isolating means for operating said circuit-breakers; said isolating means comprising a current transformer adjacent either end of the loop section, a current transformer in the tap from said section to the mains, a pilot circuit in which the secondaries of the transformers are connected, and trip devices energized from the pilot circuit and adapted to open the circuit-interrupting devices at either end of the loop section and .in the ta from said section upon a predetermined a normal condition.

14. An electric distribution system comprising a sectionalized power loop adapted to be energized fromone or more sources of power; mains; a tap connecting a loop section to the mains; means for opening the tap; circuit-interrupting devices ,ass' iated with said loop section for isolating d section from the loop; and pot utial-b neeresponsive isolating means ope ating said circuit-breakers; said iso ing means comprisin a potential transfo r adjacent either on of the loo section, a ansforn'ier in the tap from sa d section to j e main f/pilot circuit in which the secondaries distribution system comjthe transformersare connected, i

vices energized from the pilot circuit and adapted to open the circuit-interrupting devicesat either end of the loop'se'ction upon a predetermined abnol mal' condition.

5 '1-5. An electric distribution sy stem ooniprisinga sectionalized power loop adapted to be energized from one or more sources of power; mains; a tap connecting a loop section to the mains; circuit-intertupting and feeder for isolating sad section from the loop and from the mainsi, andpotential-balancere sponsive isolating means for operating said circuit-interrupting: devices; said isolating means comprising" (i; transformer adjacent either end of the loop' section, atransformer in the tap from said section to the mains, a pilot circuit in which the secondaries of the transformers are connected, and" trip devices energized from the pilot circuit and adapted to open the cirwit-interrupting devices at either. end ,Of ,the loop section-"and in the tip rom sztid section upon a predetermined: normal condition.

, 16. An electricdistributi 11 system comprising circuit-interruptingevice's, a feedor section adapted to be connected through =said circuit -interruRtin{.3,' devices to a plu- M- rality of sources of power and to a. tap to i a. load; and -a. balance pnotective system aswith eachpowerr supplyecircuit-indevices associated with said loop section terrupting device and with. the tap gand adapted upon an unbalance in the" mtective system to isolate the feeder sectilo from its sources of po wer and from the mad.-

17. An electric distribution "comprising a feeden a circuit-interrupting device therein, a balance protective system associated with the feeder section on either side of the device, each rotective system being adapted to operate the device upon an unballmce in that syste e l 18. An electric distribifi o h system com-' prising a feel ier, a-circuit jntrruptingdevice therein, a balance protective system as 'sociated with the feeder'section on either sideof the device; each protective system comprising'transformers in the feeder adjacent the circuit-interrupting device; transformers in the? feeder adjacent the other ends of said feedervsections, a pilot circuit connecting the secondaries of the former transformers with the-secondaries of the latter transformers, and means operated by said pill: circ 'ts for actuating said, circuitinterrupt 9,"

being 9.51

unbalaiici inthat stem. I

In testimony 'vv ereof, I have signed fl my 60 name to this specification this 30th day of June, 1924:.

PHILIP H. omen.

vice; ,ieaoh protective system ted to operate the deviceupon 

